Oops! Looks like Quality Control at HTC missed one! Sprint 4G EVO users are experiencing a slight problem with Android 2.2 and HTC's own calendar application. Whenever someone goes back into a calendar entry to edit the time of an event, they also have to re-enter the description of said event.
It's seems the "Where" field is overwriting the information that was entered into the event's status. It may not sound like a huge bug to some, but for people with quite a lot of meetings and appointments that change day to day, this could be very agitating.
There has been no word from Sprint or HTC of a workaround for this issue. Hopefully HTC will fix this quickly, and Sprint can get the update sent out OTA soon. The following video is an example of the discovered bug.